This invention relates to a print drum for a postage meter, and to a postage meter including a print drum.
Postage meters, also called franking machines, are well known machines used in the great majority of offices and mailing rooms throughout the industrially developed countries of the world. A print drum operates in a well known manner to make a single revolution at each operation thereby making a franking imprint on an envelope or other package which is to be franked. A print drum contains a print wheel assembly, whereby commonly four digits may be printed, each of the print wheels being rotatable so as to dispose any digit from 0 to 9 at their respective rotational positions i.e. the printing positions, in order to frank any desired currency amount on the envelope or other package. Various complex and ingenious mechanisms have been devised for rotating the print wheels of a print wheel assembly, in accordance with requirements.
Rotation of the print drum is normally effective to place other imprints, besides the franking amount, on an envelope or other package. Different countries have different rules and customs with regard to the nature and number of these extra imprints. For economy of manufacture, it is clearly desirable that a print drum design should be such as to be able to accommodate the maximum number of different imprints needed for any country, or alternatively such lesser number as other countries may require. It will be understood that when this is achieved, the same design of print drum may be used in post age meters intended for use in any country.
U.K. Pat. No. 328,332 discloses a postal franking machine which consists of a printing drum and a magazine drum which carries a plurality of printing dies for printing different monetary value. In operation the appropriate printing die is brought to a transfer location and then slid laterally onto the printing drum. The printing drum rotates between two fixed side plates which prevent lateral movement of the printing die. Further dies may be inserted at spaced locations about the printing drum when it is in a unique rest position. In this arrangement it is necessary to change a printing die each time a different monetary value is to be franked. Furthermore the removal and replacement of dies may be done only when the printing drum is at its rest position, and access to the interior of the drum is severely limited.
It is an aim of the present invention to provide a design of print drum which represents an improvement over prior knowledge.